feat: add channel metadata resolution and logo handling for enriched channel views

Entire-Checkpoint: c6e522b4276c

libs/shared/interfaces/src/lib/epg-channel-metadata.model.ts

@@ -0,0 +1,9 @@
+/**
+ * Flattened EPG channel metadata returned to the renderer for lookup-based
+ * enrichment of playlist channels.
+ */
+export interface EpgChannelMetadata {
+    id: string;
+    displayName: string;
+    iconUrl: string | null;
+}